Temperature-compensated target assembly for color-kinescopes, etc.



P 1952 R. D. FAULKNER ET AL 2,611,100

TEMPERATURE-COMPENSATED TARGET ASSEMBLY FOR COLOR-KINESCOPES, ETC

Filed Dec. 5, 1950 NVENTOR 9 e/cwmea a 5904411!!! 4/10 Mum/w A! B'A/HEPatented Sept. 16 a 1952 1 315??? FQ O R-3 5 1 3 na -am Faulkner andWilliam A. Bentley,

a cas er). B

at America;

a i s. o, Rad o. fiorpeiefiqn corporation ielavgare Application December5, 1950,: Serial No. 199,252 i i l V 7 Qlaimsi (C 313 9 This inventionrelatesto cathode-ray:'-.tuhes and particularly to improvements intargetassemblies for color-kinescopes.of'rthe .so=ca1led m asked-targetvariety;

Masked-target kinescopes are described in-the RCA publication (April1950) entitled: (General Description of Receivers for the RCA ColorIeler vision Employing the. RCA; DirecteView .Tri- Color Kinescope. The,bieparttareet -assemblies i eseribed include: ..(.i).;A" viewing screencomprising 'a' transpa ent "foundation. surface containing'a multip'citypaoi groups; of picture areas f -elemen al. ima e dimensions- Thedifierent areas, of, each; group are: coated with different phosphormaterialsh Each phosphor material, when struck bye ctronssemitslight ofa color peculiar to its posit n in. .tl ie roup.v The phosphor-coveredareas usually takeztlle. for-m of circular or hexagonal-.d9t$,'rthough;as. deseribed in French en. 8 t me risen; theymav c mpr s a mu p t pa ael arran ed-phosphor lines. The second-elem 9f. the; biepart targetassembly, .fi ipliises {ii an pertured mask. The mask is mountednear-the phosphor covered-face of the v-iewingscreen. 'rheniimber 0f p fi ithe ask i -Jless than: the number of phosphor covered areas onthesfireen. If a three-color screen is employed, the mask usuallycontains one-third a smany a ertures asnthere are p os o eas th tarsetiThe mask is scanned by one or more-electronz-beams;

When the color-kinescope is of the three-gun variety, the electron-gunsareindividual'tothe separate color-components of the phosphor .cov. eredareas of thetarget. {Ihe -beamsapproach thema sk at difierent angles; At,themask, the

beam-paths cross and diverge toimpinge uponseparate ones of thesub-elemental areasineach phosphor group If the kinescope is oi-wthe'onegun variety, the beam is deviated and rotated" to pointscorresponding-11013116 points of origin of the three-gun beama so thatitto iapproaches lmask. and target atansles i d is uai v tothe differentcolors.

Color-kinescopes using a-B" ;x i3 receiving sc containing --ai pr xiinaely 300,000 colorphosphor dots have been successfullyiconstructed andoperated. The masksfor these screens comprise taut thin-metalsheetsicqntainin approximately. 200,000 apertures,-

Certain methods em lo ed in plotting-the rela-v tive location ofthegrouped phosphor dots p ct o the m sk .holes..and. 1i=n -makingrfandmounting the screen and maskrassembly', are described and claimed byHarold B. Law in coa be substantially A sendin annlieatien Ser al: N951583 fi ed April 28495 .I assemb y; t eh n -meta mask; is stetched-filer the iap ie ticn 9i ea en; ametal a i aiiizieektherete. ininite cooling) by. .meansei screw-ever. theeliise Ehi ass-screen iecuredte. the apposite. s de Qi the ran eswithiitsphesnhorcoyered surfaeitn Semen a n he mask. .b -twc ninsorbelt Law'reeosnized that the,diiierent eoefiiei nt of expansion of the glass. screen andthe metalmask and irtime-could. causedamage to the a sembly when. it 315subiecteduto heat duringathe Me -as,- sing cycle and during. normaloperatingcycles. In: order to minimize. this: hazardLaw provides hisframe with one or. more oversize holes or slots for receivingthe 4 pins1 ort-bolts which hold the glass; SGIGBIh-Olltthfi, metal; plate. Thus,.the

stresses which might. b.e.-:1'applied to. the glass installation of thetube Withinwhich it'is in-' stalled. Nor is the-solution oi tli'is'problem found in theuse of moremounting-screws, since each 7 additionalscrew requires-the -boring of an additional hole in 'the screen and itssupporting frame.- 1 Accordingly -the principal pbject of the pres: entinvention is to provide animproved 'ten e perature-compensated;screen-assembly of f the general character described and on which shalln n s rl' i e s t r Another and related objectdill? :9 i s..ma eriali .yei dee w thei t niii -e the t me tha h tubei a the um The qrescine. andat, in accordance with the inve k facile manner by the provis on lo f a,aii ofop r pes e r t c m s which a e ,see re o th mask-supporting ram ndWit whichi he glass screen isi-supported to perm o degree of movement oncushions constituted of aspuhlglass or equivalent (i; e. easilyas-gasses)" resilient material;

3 connection with the accompanying single sheet of drawings, wherein:

Fig. 1 is a front elevational view showing the obverse or viewing sideof the glass screen of a masked-target kinescope, the glass beingsupported, in accordance with the principle of the invention oncushions" in a pair of oppositely located clamping elements;

Fig. 2 is a rear elevation of the masked-target assembly of Fig. 1,showing the manner in which the punctiform mask is affixed to the frameor support of the assembly; and

Fig. 3 is a vertical section of the masked-target assembly of Figs. 1and 2, taken on the line 3-3 of Fig. 1.

The temperature-compensated target-assembly shown in the drawingcomprises a translucent viewing-screen I, an apertured thin-metal mask3, and a metal frame 5, upon which said screen and mask are supported.The viewing screen comprises a foundation plate constituted of glass orequivalent (i. e. transparent or translucent) insulating material andits rear or target surface It will be understood to be provided with apunctiform or other pattern of electron sensitive areas, not shown. Thisplate I, as here shown, is in the form of a truncated circle, havingupper and lower horizontally extending edges Ia and lb, respectively.The mask 3 for the target surface It of the glass screen or plate I andthe central opening 5 in the frame 5 are of the same general shape astheviewing screen I. The thickness dimension of the frame 5 is indicated bythe required spacing between the mask 3 and the electron sensitivesurface of the screen. 7

The thin metal mask 3 is secured to the rear surface of the frame 5 bymeans of screws 1 which extend through metal clamping strips 8, 8a,etc., which are disposed in end-to-end relation, about the marginaledges of the mask. Wires 9, welded to the underside of each strip, maybe provided, if desired, toprevent the mask from slipping when thescrews are tightened. As described in the Law application (Serial No.158,901), the thin metal mask is. preferably heated before the screwsare tightened,.so that, upon cooling, the thin metal will contract andbe rendered taut on the frame.

Two elongated L-shape, clamping elements II and I3, which are movablysecured to the front of the frame 5 by two sets of screws I2, and I 4,respectively, hold the viewing screen or," plate I in position on theframe 5. This glass plate I is fitted in the angle of the Us (I I, I3)with the long arm of each L (I I, I 3), extending over the straightedges of the front major surface of the glass, so that the short armsofthe Us (I I, I3) are adjacent to the straight minor edges thereof.

If a clamping force were to be applied directly to the glass through theclamping elements II, I

I3 and screws I2 and I4, the different coefilcients of expansion of theglass and metal might cause the glass to crack when the assembly issubjected to the heat generated either during'normal operating periods(by the electron-beam) or during the sealing-in (or dc-gassing)manufacturing operations. In accordance with the present invention, thishazard is overcome by applying the clamping force to the glass plate Ithrough a suitable cushioning material II, which permits of a limiteddegree of relative movement between the glass plate or screen I and theframe 5 when the assembly is subjected to changes in temperature. Thecushion I1 must be constituted of a refractory material and,furthermore. the material must be of a kind capable of being thoroughlyout-gassed without unduly prolonging the time the tube is on the pump.Fibers constituted of glass and assembled either in the form of abundle, wad or fabric have been found entirely satisfactory. In theinstant case, the refractory cushioning ma terial takes the form of awoven glass tape I1 and is disposed between the marginal straight edgesof the major surface I5 of the viewing screen I and the long arms of theL-shape clamping members II and I3.

It will be observed that the construction and arrangement of theclamping elements II, I3 and screws I2, I4 is such that the glass plateis not weakened by the mounting holes required in the target assembliesof the prior art.

It will now be apparent that the present invention provides an improvedtemperature-compensated screen assembly and one which is substantiallyimmune to shocks and tremors of any ordinary intensity.

What is claimed is:

1. A temperature-compensated target and frame assembly for use in anelectron-discharge device, said assembly comprising, a foundation platehaving an electron-sensitive target surface, a frame for said plate,said plate and said frame being constituted of materials havingdifferent coeificients of expansion, mounting elements carried by saidframe in a position to engage'discrete edge portions of said plate, aresilient refractory material disposed adjacent to said discrete edgeportions of said plate, and

means for exerting clamping force upon said plate through said mountingelements and resilient material, whereby to permit of a limited degreeof relative movement between said frame and plate when said assembly issubjected to changes in temperature.

2. The invention as set forth in claim 1 and wherein said reslientrefractory material is constituted essentially of inorganic fibers.

3. The invention as set forth in claim 1 and wherein said resilientrefractory material is in the form of a fabric having a relatively looseweave to facilitate the removal of gas therefrom. I .4. The invention asset forth in claim 1 and wherein said resilient refractory materialcomprises a tape-like structure constituted of glass fibers.

5. The invention as set forth in claim 1 and wherein-said mountingelements for said foundation plate comprise a pair' of elongated L-shape members disposed with their long arms adjacent to a'common majorsurface of said plateand their short arms adjacent to oppositel-ylocated minor surface portions of said plate. v

6. The invention as set forth in claim 5 and wherein. said elongatedL-shape mounting elements for said foundation plate are supported uponsaid frame by said means for exerting said clamping force upon saidplate.

'7. -A temperature-compensated target assembly'for use in 'a cathoderaytube, said assembly comprising a translucent foundation plate having anelectron-sensitive target surface, a frame for supporting saidfoundation plate and containing a central aperture through whichelectrons may pass to said target surface, adjustable mounting elementscarried by said frame in a position to engage discrete edge portions ofsaid plate, a resilient refractory material disposed adjacent to saiddiscrete edge portions of said plate and through which a clamping forceis applied to said plate by said clamping elements, and an aperturedelectrode secured to said frame in spaced relation with respect to saidelectron-sensitive target surface of said translucent foundation plate.

RICHARD D. FAULKNER. WILLIAM A. BENTLEY.

6 REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date Rose June 14, 1949 Law Jan. 3,1950 Jensen Jan. 23, 1951 Larson Jan. 30, 1951 Levy Mar. 27, 1951 RoseAug. 7, 1951

